AT&T Business Device Activation (New Line or Upgrade)
Your box includes activation instructions. This page is the same process, just simplified.
You’ll need: wireless number + billing ZIP code Wi-Fi is required for eSIM downloadStep 1 — Power on + connect to Wi-Fi
- Turn on the phone (or tablet).
- Connect it to Wi-Fi.
- Have these ready: the wireless number you’re activating and the billing ZIP code.
Step 2 — Activate the line (pick ONE option)
Option A: Activate online
- Go to att.com/activations/activateWireless
- Enter the wireless number and billing ZIP code.
- Follow the prompts until it confirms activation.
Option B: Activate by phone
- Call 866-895-1099 from another phone.
- Follow the automated prompts.
- This number is for activation (not general customer service).
Important: Activation turns the line on. Next you still need to download the eSIM (if your device uses eSIM).
Step 3 — Download the eSIM (after activation)
- Stay on Wi-Fi.
- Most devices will show a pop-up like “Download eSIM” or “Add eSIM”. Tap it and follow the prompts.
- If you do NOT get the pop-up: go to Settings → Cellular (or Mobile Data) → Add Cellular Plan (or Add eSIM).
- Wait for the new number to appear, then confirm/finish setup.
Step 4 — Quick test
- Make a test call.
- Send a text.
- Turn off Wi-Fi for a moment and confirm mobile data works (LTE/5G).
Optional — Transfer your content
Need to move contacts, photos, messages, and apps from the old phone?
Common fixes
- eSIM won’t download: restart the device, reconnect to Wi-Fi, then try again in Settings → Cellular.
- No signal after activation: confirm the eSIM was added. If it was, call Business Customer Service.
- Number transfer (port) seems stuck: call the Port Activation Center to check status.
Support numbers
- Activate a line: 866-895-1099
- Port Activation Center: 888-898-7685
- AT&T Business Customer Service: 800-321-2000
- Need help from me: Contact Curtis Matthews
Updated February 2026.